This disclosure is generally directed to layered imaging members, photoreceptors, photoconductors, and the like. More specifically, the present disclosure is directed to multilayered flexible, belt imaging members, or devices comprised of a first layer, a supporting medium like a substrate, a photogenerating layer, and a charge transport layer, including a plurality of charge transport layers, such as a first charge transport layer and a second charge transport layer, an optional adhesive layer, an optional hole blocking or undercoat layer, and an optional overcoating layer, and wherein the supporting substrate is situated between the first layer and the photogenerating layer. More specifically, the photoconductors disclosed contain a first anticurling layer or curl deterring back coating (ACBC) to render imaging member flatness, and which layer is in contact with and contiguous to the reverse side of the supporting substrate, that is this side of the substrate that is not in contact with the photogenerating layer and which first layer, the ACBC of present disclosure, is comprised of an interpenetrating, and more specifically, a semi-interpenetrating polymer network wherein a fluoropolymer like polyvinylfluroride, fluorinated polyethylene, or polyvinylidene fluoride form the network structure having a suitable polymer, such as a polycarbonate incorporated into the resulting crosslinked matrix.
In some instances, when a flexible layered photoconductor belt is mounted over a belt support module comprising various supporting rollers and backer bars in a xerographic imaging apparatus, the anticurl back coating (ACBC), functioning under a normal machine operation condition, is repeatedly subjected to mechanical sliding contact against the apparatus backer bars and the belt support module rollers, to thereby exacerbate ACBC wear characteristics. Moreover, with a number of known prior art ACBC photoconductor layers formulated to contain a polytetrafluoroethylene fluoride particle dispersion, there results mechanical interactions against the belt support module components which can generate electrostatic charge-up, causing substantial belt drive torque increases such that at times total belt cyclic motion stalling is incurred. A further disadvantage is that an ACBC coating solution prepared to contain a polytetrafluoroethylene fluoride particle dispersion can be difficult to effect a homogeneous particle dispersion, and these particles exhibit flocculation problems thereby adversely impacting the coating solution shelf life. To resolve these and other problems, especially as these problems relate to a number of known ACBC associated mechanical problems and other disadvantages, there is provided a novel ACBC layer with scratch and wear resistance and surface lubrication to effect a contact friction reduction with the belt support module components, and which ACBC layer comprises a polymer network, and more specifically, a semi-interpenetrating polymer network in which, for example, a fluoropolymer forms the network structure with a polycarbonate penetrating inside the crosslinked material matrix.
Also, attempting to enable photoconductors comprising an ACBC layer to simultaneously possess high surface lubricity, acceptable wear and scratch resistance properties has often been a challenge as the combination of material properties that would be favored to enhance one of the properties would usually undermine the other, thus reducing the materials design latitude. These and other disadvantages are eliminated or minimized with the photoconductors disclosed herein.
In embodiments, the photoconductor disclosed includes a curl deterring back coating or ACBC layer on the reverse side of the supporting substrate of a belt photoconductor. The ACBC layer, which can be solution coated, for example, as a self-adhesive layer, on the reverse side of the substrate of the photoreceptor, may comprise a number of suitable materials such as those components that minimize the surface contact friction reduction and prevent or minimize wear/scratch characteristics of the photoconductor device. In embodiments, the mechanically robust ACBC of the present disclosure usually will cause a reduction in the layer's thickness to the extent that will adversely effect its anticurling ability for maintaining an effective imaging member belt flatness, for example when not flat the ACBC layer can cause undesirable upward belt curling, which adversely impacts the imaging member belt surface charging uniformity, manifesting into print defects, which thereby prevent the imaging process from continuously providing a satisfactory copy printout quality. Moreover, ACBC wear also produces dirt and debris resulting in dusty machine operation condition. Since the ACBC layer is located on the reverse side of the photoconductor substrate, it does not usually adversely interfere with the xerographic performance of the photoconductor, and hence decouples the mechanical performance of this layer from the electrical performance of the photoconductor (which are generally mutually exclusive), and it separates the often conflicting requirements from the charge transport layer crack and scratch resistance, respectively, and therefore permits, for example, the efficient development and use of photoconductors with ACBC having an effective reduction in surface contact friction and excellent wear/scratch characteristics.
The photoconductors illustrated herein, in embodiments, have excellent wear resistance, surface lubrication for lowering contact friction, extended lifetimes, elimination or minimization of photoconductive imaging member belt ACBC scratches, and effecting the prevention of triboelectrostatic charge build-up thereby reducing the imaging member belt drive stalling issues during an imaging belt dynamic machine function.
Also included within the scope of the present disclosure are methods of imaging and printing with the photoresponsive or photoconductor devices illustrated herein. These methods generally involve the formation of an electrostatic latent image on the imaging member, followed by developing the image with a toner composition comprised, for example, of thermoplastic resin, colorant, such as pigment, charge additive, and surface additive, reference U.S. Pat. Nos. 4,560,635; 4,298,697 and 4,338,390, the disclosures of which are totally incorporated herein by reference, subsequently transferring the toner image to a suitable image receiving substrate, and permanently affixing the image thereto. In those environments wherein the device is to be used in a printing mode, the imaging method involves the same operation with the exception that exposure can be accomplished with a laser device or image bar. More specifically, the flexible photoconductor belts disclosed herein can be selected for the Xerox Corporation iGEN® machines that generate with some versions over 100 copies per minute. Processes of imaging, especially xerographic imaging and printing, including digital, and/or color printing, are thus encompassed by the present disclosure. The imaging members are, in embodiments, sensitive in the wavelength region of, for example, from about 400 to about 900 nanometers, and in particular from about 650 to about 850 nanometers, thus diode lasers can be selected as the light source. Moreover, the imaging members of this disclosure are useful in color xerographic applications, particularly high-speed color copying and printing processes.